1. Field of the Invention
The invention is directed to a mobile arrangement for cleaning contaminated including a blower unit, a filter unit, supply air lines and discharge air lines, wherein the blower unit sucks in surrounding air, guides it through the filter for cleaning, and finally guides it out of the arrangement in the cleaned state.
2. Description of the Related Art
The area of use of arrangements of the kind mentioned above is chiefly in locally defined areas such as, e.g., waste dumps, abandoned polluted sites, composting plants, manufacturing sites, etc., where pollutants are emitted as a result of the work processes carried out there. Due to evolution of gas, movements of the soil and air, etc., pollutants in the form of gas and particles pass into the air from the subsoil and are breathed in along with inhaled air by persons working in this area.
For extensive prevention of health impairment of humans, it is known to use stationary installations for cleaning breathing air. However, these installations are only for use in stationary plants such as, e.g., offices and workshop rooms. Further, the health of those persons directly exposed to the pollutants when changing from one use to another on site must also be protected. Above all, this group consists of equipment operators of earth moving machinery and utility vehicles.
Essentially three systems are known for this purpose.
One system provides that the vehicle driver carries a respirator mask or breathing protection mask and, as the case may be, a protective suit. However, this involves a considerable restriction of comfort for the driver which, in many cases, results in that the breathing protection masks are not worn. Further, breathing protection masks and protective suits are subject to limited wearing periods, so that a continuous operation over long periods of time can be maintained only with difficulty.
For this reason, solutions have been developed which supply the cleaned air directly to the driver's cab. The driver can accordingly move within his cab without being hampered. In one solution, steel bottles or cylinders with up to 300 bar of compressed breathing air are installed outside of the cab. The breathing air is supplied to the driver's cab from the cylinders. When the cylinders are empty, they are generally refilled or exchanged for full cylinders.
Aside from the burdensome changing of cylinders or the time-consuming filling at a container station with high-pressure compressors, the distance to the station, whose length depends on the size of the dump, also restricts the use of this solution to exceptional cases. Further, the procurement and maintenance of these systems is very expensive and requires very highly qualified operators.
For this reason, mobile filter arrangements came to be arranged usually at the outer side of the vehicles. These arrangements suck air from the environment, direct this air through a filter and deliver the air which has been cleansed of harmful substances in this way into the driver's cab. Energy is supplied by a d.c. generator of the vehicle.
A mobile arrangement is known from DE-PS 44 21 911 C2, wherein the air is conducted into the filter over the outer side of the outer surface of the filter. The air flows through the filter radially in the direction of the longitudinal axis of the filter and exits the filter in a cleaned state in the region of the longitudinal axis of the filter.
With respect to construction, the filter is usually carried out in such a way that the contaminated air first flows through a coarse-dust filter and then through a fine-dust filter and, in doing so, is cleansed of solids particles. Once this has been accomplished, the air flows through an activated charcoal filter which eliminates the rest of the pollutants; thus, the activated charcoal filter is the final filter element in the through-flow direction.
It has been demonstrated with respect to these filters up to the present that the critical service life within a filter relates to the activated charcoal filter elements. This means that when the activated charcoal filter elements are already spent, the coarse-dust filter elements and fine-dust filter elements still have sufficient remaining filtering capacity for further operation. The filter capacity is proportional to the volume of the filter elements.
In conventional arrangements, the described relationships result in arrangements that are very large and heavy and therefore unmanageable if a reasonable service life, above all of the activated charcoal filter elements, is to be achieved. When it is desirable to construct compact arrangements, the service life of the activated charcoal filters will automatically be shortened with a reduction in volume of the activated charcoal filter, so that the activated charcoal filter element must be changed very frequently. In this case, every time the filter is changed, the question arises of whether the coarse-dust filter and fine-dust filter should also be changed although they are only partially spent, or whether they should be changed separately at a later date, which involves a special expenditure of labor.